The experiments in this proposal are directed towards the anatomical and functional organization of extrastriate visual cortex in the primate. There are two general sets of experiments, one on human cortical anatomy, and the other on functional organization in the monkey. In the human experiments, autopsied visual cortex is flattened, sectioned and stained for either myelin, cytochrome oxidase, or the monoclonal antibody CAT-301 to look for anatomical homologues of macaque cortical visual areas V2, V3, MT and LIP, and perhaps V3A and MST. If such homologous areas can be demonstrated in the human, this should clarify the etiology of specific perceptual defects due to cortical damage in certain patients (e.g. Pearlman et al, 1979; Damasio et al, 1980; zihl eta al, 1983). There are three experiments int he scond set of experiments on monkey organization. All of these experiments will use optical recordings, the double-label deoxyglucose technique and/or electrophysiological mapping to demonstrate and map the functional architecture. One of these experiments is directed towards area MT, where tests will be done for direction, velocity and other types of columns, and for intrinsic differences in activity. Another experiment is a test for color columns (wavelength preference maps) in any cortical visual area, with special focus on areas V1 and V4. In the final experiment, orientation columns will be labelled throughout visual cortex, in both New and Old World monkeys. The presence or absence of orientation columns in each area will serve as a criteria for homology between different areas in the two families of primate.